After a film formation process, particularly in a high-power and low-temperature process, a Si substrate may stick to a susceptor serving as a cathode. It has been considered that when plasma is generated with radio frequency (RF) power and film formation is performed, a Si substrate is charged with electrical charges, so that the susceptor and the Si substrate electrostatically attract each other and stick to each other.
When susceptor pins are brought into contact with the back surface of the substrate to lift up the substrate under the state that the substrate sticks to the susceptor, the substrate is forcedly exfoliated from the susceptor, so that great force acts on the substrate. The great force acting on the substrate causes a transfer error of the substrate due to a displacement of the substrate, or damages the susceptor pins or the substrate.
In order to suppress sticking of the substrate to the susceptor, it is necessary that proper plasma post-processing is performed according to the amount of charge of the substrate to reduce the amount of charge of the substrate. That is, it is necessary to perform removal of static electricity according to the amount of charge of the substrate. The amount of charge of the substrate varies depending on the content of the plasma processing. For example, the amount of charge of the substrate varies depending on plasma irradiation time or power under film formation.